If the earth moves round the sun in a circular orbit of radius $150000000 \mathrm{km}$ with an angular velocity of about $0.01745 \mathrm{rad} {\mathrm{day}}^{-1}$. Its linear speed in $\mathrm{km} {\mathrm{s}}^{-1}$ is approximately

Consider the following statements.

I. The gravitational force exerted by the sun on the moon is greater than the gravitational force exerted by the earth on the moon.

II. A heavy body falls at a faster rate than a light body in vacuum.

Which of the following statements given above is/are correct?

Consider the following conditions in respect of an artificial satellite.

I. It should revolve in an orbit that is concentric and coplanar with the equatorial plane.

II. It should be placed at an altitude of about $36000 \mathrm{km}$ from the earth.

III. Its period of revolution around the earth should be $24 \mathrm{h}$.

Which of these conditions must be satisfied by an artificial satellite in order that it becomes a geostationary satellite?

Select the correct answer using the codes given below,

$\mathrm{I}$. The gravitational force between two particles is independent of the presence of other bodies or the properties of the intervening medium.

$\mathrm{II}$. The gravitational force obeys Newton's third law.

$\mathrm{III}$. The gravitational force obeys Newton's second law.

A body attached to a spring balance weighs $10 \mathrm{kg}$ on the earth. The body attached to the same spring balance is taken to a planet, where gravity is half that of the earth. The spring balance will read